The present invention relates to a composition for treating hard surfaces to change the behaviour of dust which is deposited on to the surfaces, and to a process using the composition.
Various compositions containing silicones have been proposed for treating hard surfaces, in particular furniture, in order to modify the appearance of the surfaces, in particular to polish the surfaces. Current furniture polishes based on silicones operate by leaving a mobile layer of silicone fluid (or a combination with waxes and oils). Dust will settle out on furniture when furniture is exposed to the atmosphere in rooms. When dust settles on a mobile layer of silicone fluid it will remain on the surface of the silicone for a considerable time. The length of time the dust remains on the surface will depend on the viscosity of the silicone fluid in the original polish. Silicone fluids of viscosities of 20 centistokes or more are commonly used in furniture polishes and with such fluids the dust may remain on the surface for hours. When the film of silicone fluid is only a few micrometres thick the surface dust is available for redistribution into the atmosphere. Furthermore, the dust is composed of many different components, both hydrophilic and hydrophobic. The hydrophilic material may remain on the surface even when the hydrophobic material has sunk into the silicone.
It is often desirable for furniture polishes to have anti-static properties, usually in the form of enhanced surface electrostatic charge dissipation which also reduces the attraction of dust to the surface. There are numerous ways of doing this. It is thus known to provide products for treating furniture which contain an anti-static material to reduce the tendency of a surface to attract dust. However, such products are concerned with reducing the accumulation of dust on the surface rather than with modifying the behaviour of the dust after it has settled on the surface.
Polished surfaces are often dry-dusted (i.e. dust is removed with a dry dusting cloth or other dry implement) between applications of polish and the dusting procedure may cause dust on the treated surface to be redistributed in the atmosphere. Some of the components of the dust have very small particle sizes, e.g. less than 10 micrometres in diameter, and have an increased probability of being released into the atmosphere and of remaining in the atmosphere for a significant period of time. These components include pollen grains, mould spores, and faecal matter from dust mites. These components can produce an allergic reaction when respired by humans if present at sufficiently high concentrations.
U.S. Pat. No. 5,112,394 discloses a furniture polish concentrate which contains a silicone fluid (dimethyl silicone) and a siloxane copolymer containing a poly(ethoxy) chain, which copolymer acts as an emulsifier. The two components form separate layers when applied to a lacquered furniture surface. The dimethyl silicone forms the upper layer and the copolymer, which has a greater specific gravity, forms an underlying layer. The behaviour of dust on the treated surface is not discussed.
While it may be desirable to minimize the deposition of dust on a surface it has now been found that it is desirable to provide silicone-containing compositions which can bind at least certain dust components more firmly to the treated surface and that it may be desirable to agglomerate certain components of the dust.
According to one aspect of the present invention, an emulsion polish comprising a non-volatile silicone fluid, a liquid polyether siloxane which is immiscible with water and the silicone fluid, and a surfactant to stabilize the emulsion is provided wherein the polyether siloxane has a specific gravity which is less than that of the silicone fluid.
When the emulsion is applied to a surface, it is broken by wiping with a cloth or the like, as is conventional with emulsion furniture polishes. The polyether siloxane migrates to the surface carrying with it any dust which settles immediately after the application of the emulsion. When separation is complete, any dust settling on the surface will tend to agglomerate and to be drawn into the surface layer of the polyether siloxane within a short time compared with many hours when the surface layer is a silicone fluid.
The present invention is particularly useful for the treatment of hard surfaces in rooms, i.e. enclosed habitable spaces where dust deposited on hard surfaces is likely to be breathed by humans if it is re-distributed into the atmosphere. The hard surface may be a floor, in particular a wooden floor, or may be furniture placed within a room. The furniture may be of any of the materials commonly used for the construction of furniture, e.g. wood, plastics, glass.
According to a further aspect of the present invention, a process for treating a hard surface in a room comprises
a) applying to the surface an emulsion polish comprising a non-volatile silicone fluid, a liquid polyether siloxane which is immiscible with water and the silicone oil, and a surfactant to stabilize the emulsion wherein the polyether siloxane has a density which is less than that of the silicone fluid, and
b) wiping the surface to break the emulsion.
The non-volatile silicone fluid is a hydrophobic liquid material based on a siloxane chain carrying alkyl substituents, preferably dimethyl, on the silicon atoms. Silicone fluids are well known commercial materials. It is preferred to use silicone fluids having a viscosity of at least 20 centistokes, preferably at least 80 centistokes, at 25xc2x0 C., in order to maintain an even shine and significant residual film. However, it is preferred to avoid the use of silicone fluids with viscosities greater than 200 centistokes, as this will increase the time taken for particles to penetrate into the film of product deposited on the hard surface. For effective performance, an effective amount of the silicone fluid should remain on the treated surface for at least 24 hours. Preferably an effective amount should remain on the surface for at least one week, on the assumption that a fresh layer of product will be deposited at weekly intervals.
It is possible to produce volatile liquids based on dimethyl siloxane groups, usually with cyclic structures. Such volatile materials which rapidly evaporate from the layer deposited on the treated surface are not silicone fluids as required by the present invention.
Polyether siloxanes are known materials containing both polyether chains (derived from ethylene oxide or propylene oxide and chains of repeating dialkyl siloxane units).
The polyether siloxane is not miscible with either water or the siloxane fluid. This does not exclude the possibility of limited solubility in either water or the siloxane fluid but means that in the composition of the invention, the quantities of the siloxane fluid, polyether siloxane copolymer, and water are such that separate phases of each are formed when the components are allowed to settle in the absence of an added surfactant.
Many, if not most, siloxane-polyether copolymers are water-miscible and such copolymers are not suitable for use in the present invention.
Siloxane-polyether copolymers are available with various densities and it is an essential feature of the invention that the density of the polyether siloxane is less than that of the silicone fluid at ambient temperatures. Thus the density is preferably not more than than 0.95 g/ml, preferably not more than 0.94 g/ml (at 25xc2x0 C.).
Among commercially available polyether siloxanes are those with the following structures 
where R is a polyether group.
If polyether siloxanes of structure 1 are available having the required miscibility and density requirements they may be used in the present invention. It is preferred to use polyether siloxanes of structure 2, in particular those in which the siloxane structure has been modified by replacing some of the methyl groups by higher alkyl groups in addition to polyether groups. Thus the preferred polyether siloxanes are those containing pendent polyether groups on at least some of the Si atoms linked to two oxygen atoms in the backbone of the polymer, as well as alkyl groups.
An example of a particularly preferred polyether siloxane is that available from Th. Goldschmidt AG under the trade name xe2x80x9cTegopren 7006xe2x80x9d.
Many polyether siloxanes have activity as surfactants. However, the polyether siloxanes used in the present invention are not required to provide surfactant activity but to modify the behaviour of dust on the surface. The surface activity required to form an emulsion is provided by surfactant materials other than polyether siloxanes meeting the miscibility and density requirements of the present invention. Conventional surfactants which do not contain silicon are well-known and may be used in the present invention. It is preferred to use a mixture of oil-soluble and water-soluble surfactants. Examples of surfactants which may be used are sorbitan monooleate (oil-soluble) and alkylene oxide derivatives of sorbitan monoleate (water-soluble).
The composition may contain various other components which are conventional in furniture polishes, for example hydrocarbon solvents, wax, preservative, corrosion inhibitors, anti-static agents, and fragrance.
The compositions of the present invention may be used in the form of emulsions with an oil phase dispersed in a continuous aqueous phase (which may be referred to as xe2x80x9cwater outxe2x80x9d emulsions, or as emulsions in which water droplets are dispersed in a continuous oil phase (which may be referred to as xe2x80x9coil outxe2x80x9d emulsions).
The emulsions are preferably prepared by separately preparing a) an oil phase containing oil-soluble components including an oil-soluble surfactant, and b) an aqueous phase containing water-soluble components including a water-soluble surfactant, and then mixing the phases together in conventional homogenizing equipment for producing emulsions.
The composition may be used as a cream, in which case wiping to break the emulsion is simultaneous with the application of the cream. Alternatively, the composition may be applied to a surface in the form of a spray, and subsequently wiped over the surface. The spray may be applied using a dispenser with a hand operated pump, or a may be applied using gas stored under pressure from an aerosol dispenser.
The amount of the siloxane fluid in the composition may for example be 0.5 to 20% by weight, based on the total weight of composition, preferably 1 to 5% by weight.
The amount of polyether siloxane may for example be in the range 0.2 to 5% by weight, based on total weight of composition, preferably 0.3% to 1.5% by weight.
The amount of surfactant may for example be in the range 0.2 to 4% by weight based on the weight of composition, preferably 0.3% to 2% by weight.
The amount of hydrocarbon solvent may for example be 5% to 50% by weight, based on total weight of composition, preferably 10% to 15% by weight.
The quantity of water is preferably at least 50% by weight based on total weight of composition, preferably at least 70% by weight.